Synchronous injection-production energy replenishment for a horizontal well in an ultra-low permeability sandstone reservoir: A case study of Changqing oilfield in Ordos Basin, NW China

Wang, Jing; Liu, Jungang; Li, Zhaoguo; Li, Hongchang; Zhang, Jiaosheng; Li, Wenqing; Zhang, Yuanli; Ping, Yi; Yang, Huanying; Wang, Ping

doi:10.1016/s1876-3804(20)60098-2

Cited by 24 publications

(10 citation statements)

References 7 publications

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“…Except for well P3 in the well control range of P2, which was in a low-yield state for a long time, the fitting error of water production was large, and the other six wells were all fitted perfectly, with a fitting rate of 85.7% [6,7]. By fitting the dynamic and static model of quality control, its perfection degree is high, and it can objectively reproduce the reservoir development process, which lays a foundation for the subsequent design of pressure flooding water injection parameters and effect prediction [8][9][10][11][12][13].…”

Section: Historical Fittingmentioning

confidence: 99%

Integrated Design Technology of Geological Engineering for Pressure Flooding and Water Injection in Low Permeability Reservoirs: Take the Reservoir of Keshang Formation in Wu2 East Area as an Example

Qin¹,

Chen²,

Q³

et al. 2022

Journal of Chemistry

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The objective factors of low permeability reservoir determine that there is obvious starting pressure gradient in waterflooding development, and the injection pressure is high. Conventional waterflooding has the technical bottleneck of “no injection and no flooding.” It highlights the development contradictions such as serious under-injection, rapid production decline and difficult production of reserves. Pressurized water injection is a new technology of unconventional water injection to enhance oil recovery, which can improve the production degree of low permeability reservoir reserves and solve the problem of water injection difficulty. In order to ensure the reliability of scheme design and the success rate of field implementation, the key technologies of unconventional oil and gas reservoir geological engineering integration are applied for the first time, including 3D geological modeling technology, geomechanics modeling technology, complex fracture network simulation technology of geological engineering integration and numerical simulation technology, and a fine 3D dynamic and static model covering all elements of geology and engineering is objectively established. Through numerical simulation research, the optimal water injection parameters of pressure flooding are determined, and the implementation effect of the optimal scheme is predicted, which provides a scientific basis for field implementation.

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Section: Historical Fittingmentioning

confidence: 99%

Integrated Design Technology of Geological Engineering for Pressure Flooding and Water Injection in Low Permeability Reservoirs: Take the Reservoir of Keshang Formation in Wu2 East Area as an Example

Qin¹,

Chen²,

Q³

et al. 2022

Journal of Chemistry

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“…The injection of CO 2 , N 2 , and mixed gas for the enhanced coalbed methane recovery was also studied. The results revealed that the recovery efficiency of CH 4 by pure CO 2 was higher than the recovery efficiency by pure N 2 [29]. Mixed-gas injection reduces the efficiency of CH4 recovery.…”

Section: Introductionmentioning

confidence: 92%

Experimental Study of CO2-ECBM by Injection Liquid CO2

et al. 2022

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Coal mine gas disasters have severely restricted production safety. Improving gas extraction efficiency can effectively reduce disasters. Scholars have confirmed that CO2 successfully displaces coal seam CH4. This study conducted displacement and in situ experiments and compared gas drainage under different injection pressures. The displacement experiments indicated that CH4 production rates increased under increased pressures while the displacement ratios decreased. The pressure had a positive effect on sweep efficiency. The in situ experiment showed that CH4 and CO2 concentration trends in the inspection hole remained consistent. Through observing the data of the original and inspection holes, the average gas drainage concentration during low- and medium-pressure injections increased by 0.61 times and 1.17 times, respectively. The low-pressure average gas drainage scalar was increased by 1.08 times. During the medium-pressure injection, the average gas drainage purity increased by 1.94 times. The diffusion ranges of CO2 under low- and medium-pressure injections were 20–25 m and 25–30 m, respectively. The sweep efficiency of medium-pressure injection was 26% better than that of the low-pressure injection, with average pressures of 2.8 MPa and 1.4 MPa, respectively, for sweep efficiency. This study proposes an effective method for improving coal mine gas drainage efficiency.

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“…Given the rapid depletion of conventional oil production and the rising energy demand, tight oil reservoirs play a significantly important role in the development of oil and gas fields for their abundant geological reserves. − Tight oil resources in China are rich, with a geological reserve estimation of 178.2 × 10 8 t, which is mainly distributed in the Ordos Basin, Tarim Basin, Sichuan Basin, Songliao Basin, Bohai Basin, and Jungar Basin. − The staged-fracturing horizontal well technology is an effective method for the development of tight oil reservoirs. − However, the oil production of horizontal wells declines rapidly within the first few years, and the oil recovery during the primary depletion period is usually less than 10%. − Effective energy supplementation methods have become an important topic for maintaining the production rate of horizontal wells. Water huff-n-puff technology and waterflooding technology are the common energy supplementation methods for horizontal wells currently. − However, for the horizontal–vertical well patterns, the horizontal wells are not in the isolated formation units, which makes it difficult to hold the formation pressure during the huff-n-puff.…”

Section: Introductionmentioning

confidence: 99%

Parameter Optimization of Asynchronous Cyclic Waterflooding for Horizontal–Vertical Well Patterns in Tight Oil Reservoirs

Kang

Wang

Liu³

et al. 2022

ACS Omega

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Tight oil resources in China are mainly exploited by staged-fractured horizontal wells; horizontal wells face the problems of the rapid decline rate and low primary oil recovery. Pilot tests on the asynchronous cyclic waterflooding for the horizontal–vertical well pattern were carried out in recent years and achieved good performance. However, there are few studies on the influencing factors and parameter optimization of asynchronous cyclic waterflooding, which limits its wide application. This work took the tight oil reservoir in Yanchang formation, Fuxian area, Ordos Basin as its object, and the oil recovery mechanisms of asynchronous cyclic waterflooding for the horizontal–vertical well pattern were analyzed first. Then, the operation parameters of asynchronous cyclic waterflooding were optimized by the numerical simulation method. Among them, the injection proportion was optimized by the fuzzy synthetic evaluation method. Finally, the oilfield test was carried out based on the optimized parameters. The results showed that pressure disturbance and streamline deviation are the main oil recovery mechanisms of asynchronous cyclic waterflooding. The asynchronous mode of the diagonal well row is better than other asynchronous modes. For the injection time interval, injection–production ratio, and the injection and shut-in time, the cumulative oil production all show the trend of increasing first and then decreasing with the increase in these parameters. The optimal injection time interval and injection–production ratio are 0.5 T and 1, respectively. The optimal injection and shut-in time can be calculated by empirical formulas. Ultimately, the fuzzy synthetic evaluation model was established to optimize the injection proportion. Field practices showed that the average daily oil production of horizontal wells was increased from 1.7 to 3.0 m 3 with the optimized parameters, which further verified the accuracy of the optimized parameters. This research can provide theoretical support for the effective development of tight oil reservoirs.

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Synchronous injection-production energy replenishment for a horizontal well in an ultra-low permeability sandstone reservoir: A case study of Changqing oilfield in Ordos Basin, NW China

Cited by 24 publications

References 7 publications

Integrated Design Technology of Geological Engineering for Pressure Flooding and Water Injection in Low Permeability Reservoirs: Take the Reservoir of Keshang Formation in Wu2 East Area as an Example

Integrated Design Technology of Geological Engineering for Pressure Flooding and Water Injection in Low Permeability Reservoirs: Take the Reservoir of Keshang Formation in Wu2 East Area as an Example

Experimental Study of CO2-ECBM by Injection Liquid CO2

Parameter Optimization of Asynchronous Cyclic Waterflooding for Horizontal–Vertical Well Patterns in Tight Oil Reservoirs

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